Thundersnows are rare occurrences where snowfall is accompanied by thunder and lightning. These rare occurrences have given researchers a hard time in their zeal to study their characteristics and how they happen. Lake effect snow causes common thundersnows in the Great lake region around the US and Canada, but general winter-season thundersnows don’t happen that often. The US experienced thundersnow in 2015. It was broadcasted live on the Weather Channel. This thunderstorm, known as Neptune, was captured on camera when a reporter and meteorologist Jim Cantore, gave an update on the snowstorm. Neptune was seen as a purple flash spread across the sky. This rare thundersnow gave Cantore an adrenaline rush making him jump excitedly, yelling, “Oh yes, we got it, baby!” He was talking about the magnificent purple thunderstorm.
A new development in space imagery promises better research of these thundersnows. The lately deployed satellite, the Geostationary Lightning Mapper (GLM), can capture images of lightning flashes regardless of the time of the day or season. Scientists are using these images to reveal the science behind thundersnow.
Reports from ongoing research at the NASA Marshall Space Flight Center show that thundersnow flashes are larger than the normal rainfall- associated lightning. They also last longer. This was revealed through a study on GLM’s data from 2018 to 2020. This data indicated about a million instances where thundersnow occurred. This data confirmed previous studies that show rainfall –associated thunderstorms occur more often than thundersnows. This research is yet to be published. It is a collaboration between NASA’s scientists and Sebastian Harkema, University of Alabama’s student of atmospheric science.
During a regular thunderstorm, the humid air close to the earth’s surface rises and condenses to form clouds. Water in the clouds forms ice particles that spin around and collide. These particles exchange opposite electrical charges. Opposite charges build up on one side of the cloud. When they move suddenly towards the oppositely charged end, a flash of lightning is seen. For thundersnow, electrical charges take more time to build up in clouds. This is due to the cold winter weather. However, when they build up, they generate a bolt of stronger and long-lasting lightning that is spread out across the sky.
According to Harkema and his peers, when cloud tops change their appearance, it is the start of thundersnow. These changes were captured over time by the satellites. The images showed a gradual change in the physical appearance of cloud tops from fluffy to icy. As the ice particles reduce in size and break apart, this initiates the thundersnow. Unlike the regular thunderstorms seen in summer, thundersnows do not present a direct threat to people. This is because it rarely happens, and when it does, the people are indoors. Extremely cold weather during winter pushes people into staying inside.
Thundersnows are likely to occur during heavy snowfall periods. This discovery promises a better weather forecast. Meteorologists could estimate the snowfall rates and warn the public accurately for better preparation and taking precautionary measures. Other researchers have praised the GLM as a breakthrough. “The Geostationary Lightning Mapper is an excellent tool to be able to really capture all the lightning that happens in these more rare scenarios like thundersnows,” stated Eric Bruning, who works at the Texas Tech University as a meteorologist.https://minernews.io/